HVAC Controller Alarm Logic to Reduce False Service Calls

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

HVAC systems generate unnecessary service alarms, leading to unwarranted service calls, as they often alert for issues that are either DIY solvable or automatically fixed, such as filter replacement and defrost cycles, rather than indicating a genuine need for professional service when the system cannot maintain desired temperature conditions, causing discomfort.

Innovation Solution

An HVAC system with a processor that monitors operating conditions and generates a master service alarm only when the system fails to meet comfort parameters, distinguishing between true service needs and self-resolvable issues by considering anomaly conditions and conditioning operating states, thereby reducing false alarms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the HVAC system generates service alarms for all detected issues, then the system provides comprehensive monitoring and early warning, but it produces false alarms for self-resolvable issues like filter replacement and defrost cycles

Engineering Contradiction:
Improvealarm accuracyVSAvoidalarm generation logic
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The alarm generation logic is segmented into distinct categories: critical service alarms for genuine system failures, informational alerts for self-resolvable issues, and silent conditions for normal operational variations. This segmentation allows the system to differentiate between alarm types based on the nature of the detected issue, improving reliability by preventing false alarms while maintaining comprehensive monitoring capability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary analysis of detected issues before generating service alarms by evaluating whether the issue represents a genuine system failure or a self-resolvable condition. This preliminary action filters out false alarms for conditions like filter replacement and defrost cycles before they reach the service alarm stage, while still maintaining monitoring for actual critical failures

Inventive Principle:
Principle #10Preliminary action

2Loss of information

If the HVAC system generates frequent service alarms, then users are notified of potential issues, but service providers receive unnecessary service calls for DIY-solvable problems

Engineering Contradiction:
Improveservice need informationVSAvoidservice call time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The system extracts and separates self-resolvable issues from critical service needs by implementing distinct alert pathways. Informational alerts for DIY-solvable problems like filter replacement are extracted from the critical service alarm stream, allowing users to address these issues themselves without scheduling service calls, thereby eliminating unnecessary service call time while preserving accurate information about genuine service needs

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system enables self-service by providing users with informational alerts for conditions they can resolve themselves, such as filter replacement reminders and defrost cycle notifications. This allows users to take appropriate actions without professional service intervention, reducing unnecessary service calls while ensuring critical failures still trigger proper service alarms

Inventive Principle:
Principle #25Self-service

3Measurement precision

If the HVAC system monitors multiple operating conditions, then it can detect genuine system failures, but it increases the complexity of determining true service needs

Engineering Contradiction:
Improvesystem state detectionVSAvoidservice need determination
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The system applies different evaluation criteria to different monitored parameters based on their local quality and significance. Critical parameters like compressor failures and heat exchanger issues trigger service alarms with high priority, while less critical parameters like filter status or defrost cycles generate informational alerts. This local quality approach simplifies the determination of service needs by matching the response level to the severity of each specific condition

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS10192422B2HVAC system and an HVAC controller configured to generate master service alarms
Publication Date: 2019.01.29 LENNOX IND INC
  • US10192422B2 patent drawingFigure N/A

AI summary

A method of generating an alarm based on temperature conditions within an enclosed space. The method includes receiving, by a processor of a heating, ventilation, and air conditioning (HVAC) system, operating-condition information of the HVAC system, determining, by the processor from the received operating-condition information, whether temperature within the enclosed space is approaching a setpoint temperature. Responsive to a determination that the temperature within the enclosed space has failed to approach the setpoint temperature, determining by the processor, whether anomaly conditions exist and responsive to a determination that the anomaly conditions do not exist, generating the alarm.